Device and method for repairing components by additive manufacturing

Abstract

The present invention relates to a device and a method for repairing a component by additive manufacturing. Deviations of the surface of the component from a predetermined dimension within a repair area are determined along a specified tool path. In a subsequent filling cycle, selective application of a filler is carried out along the specified tool path.

Description

Technical Field

[0001] The present invention relates to a device and a method for repairing components by additive manufacturing, in particular for repairing indentations in components. Background Art

[0002] For the repair of damaged components, the repair site is usually ground in the first step. In the next step, the ground part is scanned and a corresponding computer model is created. Based on this data, a structural model is created, which can be inserted into the ground part to repair the damaged area. This repair process can repair the damaged area on the surface of the component, thus restoring the original surface. The structure to be inserted can be produced using an additive manufacturing process and incorporated into the ground part.

[0003] A known repair method is, for example, US 2017 / 0370221 A1. In this method, the first step is to remove the defect from the component to be repaired. The repaired component can be created by an additive manufacturing method so that the component can retain its original geometry. However, a disadvantage of the known method is that, in order to create the structure, multiple data conversion steps and processing steps of the measurement data are required, and then the structure can be manufactured from the measurement data of the component to be repaired using an additive manufacturing method. This means that the data usually needs to be processed. This results in a high computational load and a large amount of data.

[0004] Based on the above prior art, the object of the present invention is to solve the said problems. In particular, the object of the present invention is to provide an effective method for repairing components using additive manufacturing and a corresponding device. Summary of the Invention

[0005] To achieve the above object of the present invention, the features of the independent claims are proposed and preferably developed in the dependent claims.

[0006] According to the present invention, a method for automatically repairing a component using an additive manufacturing system may include a first step in which a defective component is clamped into the manufacturing system. In a further step, a repair area including the surface of the component to be repaired may be defined. A tool path may also be set within the repair area. The tool path corresponds to the path along which the tool of the manufacturing system travels in one cycle. In the next step, the condition of the component within the repair area may be determined (= measurement cycle). In such a measurement cycle, data values may be determined along the set tool path. The data values correspond to the deviation of the component surface from a specified allowance. Specifically, the determined deviation may be the depth (or its absolute value) of the damaged area at a certain point (measurement point). In a further step, a filler or filling material may be selectively applied. The filler may be applied along the set tool path within at least one filling cycle. In the filling cycle, part or preferably the entire tool path may be moved, and the manufacturing system may be selectively activated to apply the filler according to the difference between the data value on the path and a predetermined threshold. This advantageous method can use the data directly generated in the measurement cycle as the direct input for the filling cycle. Thus, a data array containing measurement values of various path points (measurement points) is created in the measurement cycle. This data array in turn is the input for the filling cycle, and after comparison with the predetermined threshold, the activation or deactivation of the manufacturing system for applying the filler is determined.

[0007] In other words, in the filling cycle, the manufacturing system moves the set tool path along the path points. The data values that may have been determined for each path point are compared with the threshold. When a path point is reached, the tool head (e.g., a laser) of the additive manufacturing system is activated, and material can be applied. When the next path point is reached, the comparison is made again to determine whether the tool head is deactivated or remains activated. Thus, it is advantageous that the program for the filling cycle is directly created in the measurement cycle, so no further data conversion is required, and the data values are directly used to activate or deactivate the tool of the manufacturing system. Since the tool path may be the same in the measurement cycle and the filling cycle, the computational workload and the amount of data can be further reduced. In addition, the measurement cycle and the filling cycle can be automatically executed, enabling a substantially automatic repair of the component. There is no need for complex and error-prone data conversion of the point clouds of the measurement values (which may result from measuring the damaged area of the component). Thus, a simplified method for repairing components by additive manufacturing is achieved in a particularly advantageous manner, which at the same time has a low failure sensitivity.

[0008] The tool path may include a large number of path points. In the measurement cycle, the deviation between the component surface and the desired shape in the tool direction (e.g., the Z direction) may be determined at each path point. For example, the tool direction may be a direction orthogonal to the component surface in the repair area.

[0009] Advantageously, the data value can indicate the deviation of the component surface in the tool direction, and the tool direction can be orthogonal to the workpiece surface (such as the XY plane) on which the tool path lies. Thus, a tool (such as a laser) of the additive manufacturing system moves along the tool path on the workpiece surface. For example, the tool path or the workpiece surface may be orthogonal to the tool direction for determining the deviation.

[0010] In a filling cycle, the filler can be selectively deposited along a path segment of the set tool path. Thus, the filler can be applied during the travel from one path point to an adjacent path point. Whether the tool of the manufacturing system for applying the filler is turned off is determined at the target path point according to the difference between the data value at the target path point and a predetermined threshold. For example, if the tool moves from one path point to the next along the tool path and always exceeds the threshold, the laser can be continuously activated, for example, so as to always apply the filler. For example, powder coating can be regarded as additive manufacturing. If a path point with a data value less than the threshold is reached during the travel, the laser or the tool head is turned off. The laser is only activated again when another path point with the relevant data value exceeding the threshold is reached.

[0011] A path segment can be defined by two path points, and the path segment preferably extends along a straight line. Further simplification of the repair method can be achieved by this particularly effective and simple configuration of the path segments (which together form the tool path), especially because curved segments are avoided and only movements in the X direction and the Y direction are required. The data value can preferably also be the average value of the path points of the segment. Thus, the tool can also be activated segment by segment.

[0012] Within a filling cycle, the threshold may be constant. Thus, in the filling cycle, the tool of the manufacturing system can move along the specified tool path within the entire repair area, where each data point is compared with the threshold of the filling cycle. After the filling cycle is completed, another filling cycle with a modified threshold can be arranged. This configuration of the filling cycle enables continuous repair of defects. Thus, a plane orthogonal to the tool direction is defined in each filling cycle. Each plane in turn has a different threshold until the smallest threshold appears in the last plane so as to obtain the final surface (such as a plane) of the component in the repair area. Particularly advantageously, after the smallest threshold is reached, an additional oversize can be applied. For example, after the smallest threshold is reached, the filler can be applied to the entire repair area in one (or more) additional filling cycles.

[0013] Multiple filling cycles can be executed, and each time the threshold can be adjusted according to a thickness value until there is a substantially uniform surface in the repair area. In the repair area, the original surface shape (such as linear or curved) of the component can be restored. For example, the thickness value can depend on the height of the material applied in the filling cycle.

[0014] The result of the measurement cycle can be an array of determined data values. A threshold can be set for the first filling cycle based on the maximum or minimum (extreme) value of the array and a constant. In particular, the maximum value of the array is used to find the deepest defect in the repair area. Based on this deepest point, a threshold can be set so that only the deepest damaged area is filled in the first filling cycle. In subsequent filling cycles, successively reduced thresholds are used to fill other areas with the filling material. By connecting successive filling cycles, the damaged area is completely filled.

[0015] The threshold can be reduced in further filling cycles based on the thickness value, which corresponds to the height of the filler applied in the filling cycle, especially at path points or path segments. For example, the height is the height of the weld.

[0016] The determined data values of the measurement cycle can be directly used for the filling cycle. Thus, there is no need to convert or digitize the result of the measurement cycle. Therefore, a particularly efficient and simple repair method can be provided. In addition, frequent errors usually caused by conversion errors are avoided.

[0017] The data values (without data conversion) can be compared with the threshold in the filling cycle. Thus, the unconverted data values from the measurement cycle are directly used to decide whether to activate or deactivate the tool of the adaptive manufacturing system (i.e., whether to add material) by comparing with the threshold at the corresponding path point.

[0018] Therefore, the method can be an advantageous method for creating a flat and / or curved surface in the repair area. Advantageously, the shape of the repaired surface corresponds to the original surface shape of the component.

[0019] Advantageously, the tool path can be defined taking into account the working diameter of the manufacturing system. For example, the working diameter of the adaptive manufacturing system can be the diameter of the laser (in the case of powder coating). Taking into account this working diameter, the tool path can be advantageously defined so as to completely cover the entire repair area.

[0020] The tool path can be a non-overlapping continuous polyline. More preferably, the tool path can be curved. The tool path can also consist of straight line segments, each straight line segment extending along a straight line. Therefore, an optimized tool path can be provided for a particularly error-free method. In addition, the tool path can be configured to be parallel to the contour of the repair area.

[0021] The repair area can be specified so as to completely cover the area of the component to be repaired. Thus, it can be achieved that the method can produce a flat surface (or advantageously, also a curved surface according to the original component shape) at the repair location.

[0022] During the final filling cycle, as the tool of the additive manufacturing system travels along the set tool path, the tool can be advantageously activated continuously. This process can flatten any possible unevenness. In addition, an oversize can be provided throughout the repair area.

[0023] The defined tool path is advantageously the travel path of the tool of the additive manufacturing system and also the travel path of the measuring instrument for determining the deviation. Therefore, there is no need to switch the travel path or the tool path between the measuring cycle and the filling cycle or all filling cycles. Thus, the computational workload can be further reduced and the sensitivity to errors can be minimized.

[0024] The tool of the additive manufacturing system can move from one path point to an adjacent path point along the set tool path, where the determined data value of each path point can be compared with the threshold of each path point, and when the threshold is exceeded, the tool can be activated. On the other hand, when the value is below the threshold, the tool is deactivated (and vice versa for the case of reversed plus and minus signs). Advantageously, the measured values at the path points can thus be used to directly provide a command array to activate or deactivate the laser or the tool of the additive manufacturing system.

[0025] Particularly advantageously, the measuring cycle and the subsequent filling cycle are automatically executed, so no manual intervention is required. The measuring cycle and all subsequent filling cycles are also advantageously automatically executed. Thus, the data values of all filling cycles are the same. Alternatively, in order to improve the accuracy, a further measuring cycle can be advantageously provided after each filling cycle.

[0026] The method can be a method of filling the indentations on the surface of the component within the damaged area.

[0027] The method advantageously includes the steps of moving the tool along the path points of the set tool path, activating the laser when reaching a path point where the data value is greater than the threshold, and deactivating the laser when reaching a path point where the data value is not greater than the threshold. A large number of filling cycles can be provided, in which case the threshold can be reduced from one filling cycle to another. Advantageously, the threshold of the final filling cycle is reduced so that all data values of any data point are greater than the threshold. Particularly advantageously, the threshold can be set so as to apply multiple oversize layers in the repair area.

[0028] Advantageously, the set tool path can include parallel segments, and the distance between adjacent segments can be determined according to the working diameter of the laser.

[0029] The additive manufacturing system can include a laser, and the laser is turned on and off at the path point according to the comparison result between the data value of the path point and the threshold.

[0030] Advantageously, a measuring probe or an optical sensor can be used to measure the cycle (for determining data values). Additionally, capacitance and / or inductance sensors can be used for the determination.

[0031] Advantageously, a device for data processing can be provided for performing the above method. Additionally, a computer-readable storage medium can be provided that includes instructions which, when executed by a computer, cause the computer to perform the above method. An additive manufacturing system can be provided that is configured to perform the above method and includes a corresponding computing unit for this purpose.

[0032] The present invention will be described below with reference to the accompanying drawings using examples. Description of the Drawings

[0033] Figure 1 : A general view showing a surface to be repaired with a marked tool path PF;

[0034] Figure 2 : A detailed view showing the tool path PF;

[0035] Figure 3a : A first view showing the filling cycle;

[0036] Figure 3b : A further view showing the filling cycle;

[0037] Figure 3c : Another view showing the tool path in the filling cycle;

[0038] Figure 3d : A view showing a well advanced filling cycle;

[0039] Figure 3e : A view showing the final filling cycle;

[0040] Figure 4 : A detailed view showing the tool path in the filling cycle. Detailed Description

[0041] The following features of the exemplary embodiments can be combined in whole or in part, and the present invention is not limited to the described exemplary embodiments. In the drawings, the same reference numerals designate the same or similar features.

[0042] The present invention relates to an optimization method for automatically repairing components such as display damage. Such damage may be bumps, scratches, grooves, etc. In order to repair indentations in the component, a method for minimizing the computational effort is proposed. Thus, data processing can be reduced to a minimum, while conversion errors that often occur can be avoided. According to the present invention, since the data from the measurement cycle is directly used as the input for the filling cycle, there is no need to additionally process the measurement data to create a model (e.g., a CAD model) that can be used for repair. In such a filling cycle, materials are applied layer by layer to the component using additive manufacturing. The present invention can be particularly advantageously used in laser-based additive manufacturing methods.

[0043] A first view of the repair area O is shown in Figure 1 . The repair area O completely covers the surface of the metal component to be repaired, where the edge of the specified repair area O has a minimum distance from the surface to be repaired. As Figure 1 shown, the damage D to be repaired on the component is an indentation. The indentation is completely filled using the method according to the present invention, so that the component has a flat surface at the end of the method.

[0044] Figure 1 An exemplary tool path PF is shown. The tool path PF defines the path along which the tool of the manufacturing system moves within one cycle. However, the tool path PF is not limited to the Figure 1 shown linear configuration and may also include curved segments. However, advantageously, the tool path PF only includes linear parts, so that the computational effort can be further reduced. The tool path PF can also be advantageously defined according to the working diameter (WorkDia). For example, as Figure 1 shown, the diameter of the manufacturing system is the diameter of the laser. According to the diameter of this laser, the distance between adjacent segments of the tool path PF is determined. Particularly advantageously, the distance between two adjacent line segments of the tool path PF is at least equivalent to half of the working diameter plus 5%. For this particularly advantageous distance, very reliable repair results are obtained.

[0045] Figure 1 The shown tool path includes, for example, a rectangular outer tool path PF and a curved inner tool path PF, where the starting point and the ending point are arranged opposite to each other. The tool path can be a continuous tool path or can also be advantageously divided into multiple spaced tool paths. Advantageously, the line segments of the tool path PF do not overlap. The tool path PF is set to cover the entire area within the repair area O while taking into account the working diameter. The tool path PF remains unchanged in the measurement cycle and the filling cycle, thereby further reducing the computational effort and the amount of data. Figure 1The view shown uses the XY plane as an example, which is a plane here. The deviation between the surface of the component and the specified allowance is measured in the tool direction (e.g., the Z direction), and at the same time, the data value DW is formed. For example, the tool direction is the direction in which the tool of the manufacturing system applies the filler.

[0046] Particularly advantageously, the tool path PF can also be an uninterrupted route of a line continuously extending from the starting point to the end point, and (always) includes straight line segments that preferably do not overlap. In this case, the arrays generated in the measurement cycle can also be directly used for the filling cycle, corresponding to the path points. In one embodiment, curved segments can be used. For example, polylines can be used as line segments.

[0047] A detailed view of the repair area O is as Figure 2 shown. Here, the tool path PF is composed of path points PFp. These path points are strung together with the path segments PFs between them. In this example, these path segments PFs are straight line segments. The distance between adjacent path points PFp can vary along the tool path in order to provide the optimal path points PFp. However, in particular, the path points PFp can be evenly distributed over the entire tool path PF, with at least one additional path point PFp provided at each corner of the tool path PF (as Figure 2 shown). At such a corner point, for example, the direction of the tool path PF may change.

[0048] In addition, Figure 2 The arrows shown in indicate the direction in which the tool of the manufacturing system, especially the laser, moves along the tool path PF. The tool path PF directly above the damaged area is preferably a single uninterrupted tool path that passes through once in one direction in a cycle. For example, when the tool needs to be removed or retracted (e.g., in the tool direction), the tool path is interrupted, so that filling cannot be performed. In another advantageous embodiment, the tool path is configured so that in the filling cycle, it only approaches the part where the filler is to be applied. In such an embodiment, the tool path in the filling cycle may be different from the tool path in the measurement cycle. In addition, for different filling cycles, the tool paths may be different.

[0049] As Figure 2 shown, the data value DW determined for each path point PFp is provided.

[0050] The first step of the method for repairing a component using additive manufacturing is to clamp the component to be repaired in the manufacturing system. Once the component enters the manufacturing system, a repair area can be defined that covers all (or only a part) of the surface of the component to be repaired. Then, the tool path PF can be defined within this repair area. All these steps can be regarded as an initialization process.

[0051] After initialization, a measurement cycle and multiple filling cycles can be performed, preferably fully automatically. In the measurement cycle, the manufacturing system can automatically determine the depth values of all path points PFp of the tool path PF in the Z direction (or generally in the tool direction). This is described in Figure 2 by the name Z_result[n]. Thus, the data values are, for example, the measured values in the Z direction (or generally the tool direction) at the path point PFp. In a particularly advantageous embodiment, these measured values are stored sequentially in a data array. Thus, the data array can be regarded as an ordered arrangement of the measured depth values. The depth values can be measured relative to a predefined zero plane, which, for example, corresponds to the ideal surface depth of the component.

[0052] After the data values have been determined and the data array has been created, the first filling cycle can be carried out directly, in which the damaged areas of the component in the repair area O are selectively filled using an additive laser. Such a filling cycle is as shown in Figures 3a to 3e . In an exemplary first filling cycle, as shown in Figure 3a , the tool of the additive manufacturing system moves along the entire tool path PF. For each path point PFp reached, the corresponding data value is compared with a threshold value. The threshold value is set according to the determined depth of the damaged area. In the first filling cycle, as shown in Figure 3a , the maximum value in the data array is determined and the maximum value (or preferably a value approximately 1% lower) is used as the threshold value. Thus, in the first filling cycle, only the damaged areas with the maximum depth are filled. In the first filling cycle, any areas with a shallower damage are not filled with the filler. This is also as shown in Figure 3a , where the activated laser A is shown as a solid line along the tool path PF. In the sections of the tool path where the threshold value is not reached or exceeded, the laser is deactivated B, as shown by the dashed line in Figure 3a . Thus, in Figure 3a , only the innermost areas of the damaged areas are filled with the filling material.

[0053] In subsequent filling cycles, as shown in Figure 3b , the threshold value is modified. Specifically, the threshold value is reduced, for example, by the filling height applied in the first filling cycle (e.g., the calculated weld thickness). Thus, since the threshold value has been further reduced, in the filling cycle shown in Figure 3, the filler must be applied to a larger area of the damaged area. The laser is activated A in the laser processing area determined in the first filling cycle and in the additional areas beyond the respective data values of the path points that exceed the threshold value.

[0054] Similarly, in Figure 3c and Figure 3d , the filling area increases and the laser is activated A in a larger area in each case.

[0055] Figure 3e Shows a final filling cycle, for example, in which the laser is activated substantially continuously A. The laser is only deactivated B in the horizontal section between two adjacent line segments of the curved tool path PF to further improve the surface quality.

[0056] Figure 4 Shows a detailed view of a filling cycle. When a path point PFp above the threshold is reached in the travel direction of the laser, the laser is activated A between two adjacent path points PFp. The laser is only deactivated B when the data value is again below the threshold when reaching the path point PFp. For all path points with a data value below the threshold, the laser remains deactivated, or if it was previously activated, the laser is deactivated. The activation and deactivation of the laser according to the measured data value above the threshold are described in this exemplary embodiment. However, it is also possible to reverse these signs. In other words, the measured value in the tool direction can be considered negative. In this configuration, the laser is activated when the data value is below the threshold. However, the above description of activating the laser when the data value exceeds the threshold typically relates to the absolute value of the measured depth in the repair area.

[0057] The surface of the component to be repaired can also initially be curved (even three-dimensionally curved). Thus, the original curved surface can be restored in the repair area by the method according to the invention. The measurement direction preferably corresponds to the tool direction and can preferably be arranged orthogonally to the component surface in the measurement cycle so that the desired depth of the damaged area can be determined. The tool path preferably also lies on a surface parallel to the original (i.e., undamaged) surface of the component. Thus, the absolute direction of the measurement may vary depending on the measurement point, for example when measuring along a curved surface. This depth can be refilled accordingly in the filling cycle. The application layer of the tool in the filling cycle is preferably applied in the tool direction.

Claims

1. A method for automatically repairing a component using an additive manufacturing system, the method comprising the following steps: – a) Designating a repair area (O) including the surface to be repaired of the component and setting a tool path (PF) within the repair area (O); – b) Determining a data value (DW) of the deviation of the surface of the component from a specified allowance by following the set tool path (PF), and determining the condition of the component within the repair area (O) in one measurement cycle using a measuring instrument of the additive manufacturing system; And – c) Selectively applying a filler along the set tool path (PF) using a tool of the additive manufacturing system within at least one filling cycle, where part or all of the tool path (PF) is traversed in one filling cycle, and the manufacturing system for applying the filler is selectively activated based on the difference between the data value (DW) and a pre-determinable threshold value, where the tool path (PF) corresponds to the travel path of the tool of the manufacturing system in at least one filling cycle and of the measuring instrument for determining the deviation; And where the tool of the additive manufacturing system moves from one path point (PFp) to an adjacent path point (PFp) along the set tool path (PF), and at each path point (PFp), the determined data value (DW) of the corresponding path point (PFp) is compared with the threshold value, and the tool is activated when the threshold value is exceeded.

2. The method according to claim 1, wherein the tool path (PF) comprises a plurality of path points (PFp), and wherein in step b), the deviation between the surface of the component and the desired shape is determined at each path point (PFp) in the tool direction.

3. The method according to claim 1 or 2, wherein the data value (DW) indicates the deviation of the component surface in the tool direction, and wherein the tool direction is orthogonal to the selected surface on which the tool path (PF) lies.

4. The method according to claim 1, wherein When the determined data value (DW) of a path segment (PFs) or a path point (PFp) of the specified tool path (PF) is greater than or equal to the threshold value, the filler is selectively applied along the path segment (PFs) of the set tool path (PF) in one filling cycle.

5. The method according to claim 4, wherein a path segment (PFs) is delimited by two path points (PFp), and the path segment (PFs) extends in a straight line.

6. The method according to claim 1, wherein the threshold value is constant in one filling cycle.

7. The method according to claim 1, wherein a plurality of filling cycles are performed, and the threshold value is adjusted by a thickness value each time until the final surface appears in the repair area corresponding to the target surface.

8. The method according to claim 1, wherein the result of step b) is an array composed of the determined data values (DW), and the threshold value of the first filling cycle is set based on the maximum or minimum value and / or a constant of the array.

9. The method according to claim 1, wherein the threshold is adjusted based on the thickness value in a further filling cycle, and wherein the thickness value corresponds to the height of the filler applied in a filling cycle.

10. The method according to claim 1, wherein the determined data value (DW) of the measurement cycle is directly used for the filling cycle.

11. The method according to claim 1, wherein the determined data value (DW) is used to compare with the threshold in the filling cycle without data conversion.

12. The method according to claim 1, wherein the tool path (PF) is defined considering the working diameter (WorkDia) of the manufacturing process and covers the entire repair area (O).

13. The method according to claim 1, wherein the tool path (PF) is a non - overlapping continuous polyline configured in a curved shape.

14. The method according to claim 1, wherein the set tool path (PF) is the travel path of the tool of the additive manufacturing system and the travel path of the measuring instrument for determining the deviation.

15. The method according to claim 1, wherein at least steps b) and c) can be fully automatically executed.

16. The method according to claim 1, wherein step c) comprises: Move the tool along the path points (PFp) of the set tool path (PF), wherein, when reaching the path point (PFp) where the data value (DW) is greater than the threshold, the laser is activated (A), and when reaching the path point (PFp) where the data value (DW) is not greater than the threshold, the laser is deactivated (B), and wherein, after one filling cycle, there is a further filling cycle, wherein the threshold is reduced.

17. The method according to claim 1, wherein the set tool path (PF) includes parallel segments, and the distance between adjacent segments depends on the working diameter of the laser.

18. The method according to claim 1, wherein the additive manufacturing system includes a laser, and step c) includes: Opening and closing the laser at the path point (PFp) according to the comparison result between the data value (DW) and the threshold at the path point (PFp).

19. The method according to claim 1, wherein a measurement probe, an optical sensor, a capacitance sensor or an inductance sensor is used to determine the deviation.

20. An additive manufacturing system, comprising means for data processing, which includes means for performing the method according to claim 1.

21. A computer - readable storage medium, comprising instructions that, when executed by a computer, cause the computer to perform the method according to claim 1.

22. Use of the additive manufacturing system according to claim 20 for repairing components by powder cladding.

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